[mrerick]

Your numbered magazine is an armorer's replacement (indicated by the "42" stamped on the base).

I don't see a thing in your pictures that would want me to replace the side plate.

Lugers were all hand fitted at great expense. The trigger linkage was probably the most critical part to get right.

Your side plate is also a "42" marked armorer's replacement likely done in the field or a unit level armory. I would not consider changing it. "42" was Mauser's military supplyer concealment code after S/42 in about 1940, followed later by "byf" and (on P.38 pistols) "svw". Their armorer replacement parts were numbered with the 42 concealment code.

Your holster is a police style holster, and similar in appearance to the P.38 holster. I cannot makeout details from the pictures, but Jerry Burney on this site (lugerholsterrepair) can do a nice job of repairing stitching with original materials and refreshing it if you choose to.

I particularly like these 1936 pistols because they were rust blued and the finish quality was often nice and deep black like this one.